Total energies for various impurities and defects in HgTe, CdTe, and ZnTe are calculated. Calculations were done using a self-consistent linear muffin-tin orbital (LMTO) method within the local density and atomic spheres approximation. We calculate the total energy for substitution on both lattice and interstitial sites, and estimate the lattice strain energies. Estimates of the variation with the alloy predict a linear variation of the substitution energy with the local concentration. We predict that the Te antisite will be more prevalent in all three of the compounds than previously thought. The problem of cross doping during heteroepitaxy on GaAs is predicted to be greater on the cation sublattice. © 1990, American Vacuum Society. All rights reserved.